What does dieseling mean? – Part 3

Before we begin, a word to those who are having difficulty emailing Pyramyd Air. They recently changed their email program and the one they use now is more sensitive to blocking spam. Some ISPs (Individual Service Providers – the place where you pay for your internet connection) are known for their spam, and if the Pyramyd email software detects them, it may discard your email without giving you any status. If you can’t get an answer, I recommend you call them at 888-262-4867. They have worked hard to reduce the phone wait time and, while it’s still not perfect, hold times are much shorter.

Well, this three-part posting is turning out to be one of your all-time favorites. It seems we have a great number of spring gun fanciers in the audience.

Intentional dieselingLet’s look at how a gun can be made to diesel intentionally, starting with the famous Weihrauch HW Barakuda EL54. That was a standard breakbarrel rifle, the HW 35, to be specific, with a tube on the right side to inject a small shot of ether vapor into the compression chamber just before the shot was fired. I covered it in a special post last year, so you can read all about it there if you want to. The point is thst manufacturers recognized the power potential of a detonation and tried to harness it to make airguns shoot faster. Today, we would call the EL54 a firearm, because that is exactly what it is.

You don’t have to be an airgun manufacturer to make a spring gun diesel. Now that you know how it works, you’ve probably figured out it takes just some fuel coming in contact with the superheated, compressed air generated by the piston. Children have known this trick for at least half a century, which is the basis of the Oil-Can Louie story I mentioned in the previous post. However, that story ends with the destruction of the airgun, so please don’t experiment that way.

Deception through dieselingGamo sells a .177 breakbarrel spring rifle called the Hunter Extreme, which they claim is capable of generating 1,600 f.p.s. with PBA pellets. When a friend of mine chronographed his, it was shooting just over 1400 f.p.s. Many of you know that I asked for any reader with a Gamo Hunter Extreme to chronograph their rifle and to tell us the numbers. To date, no one has come forward. Gamo used to show a film clip on their website from the Shooting USA TV program that shows a shot chronographed at more than 1600 f.p.s. I tested a PBA pellet in a .177 Condor and it went only 1486 f.p.s., which tells me something might be fishy about Gamo’s claim. However, it is possible to make a pellet go as fast as that televised shot with some trickery.

All it takes is a pellet with a partial drop of a volatile substance like diesel fuel in its hollow base and you will get velocity figures like that. Forget accuracy at that speed, but the velocity will be there. That’s all some people want to see. The gun may not hold up long with that kind of abuse, and I do not recommend that anybody attempt it. As far as I know, this is the only way to get a pellet from a spring-piston airgun going that fast without extra mechanisms, such as an ether injector.

Daisy used the principle, too!In the late 1960s, Daisy put the caseless cartridge of Jules Van Langenhofen into production in a rifle that ignited the solid propellant using the heat of rapidly compressed air. Theoretically, their gun was a .22 caliber spring-piston rifle that just happened to shoot a caseless .22 as powerful as a conventional long rifle. In practice, the bore was too large for pellets, and any .22 pellet you tried to shoot in it was hopelessly inaccurate as well as being underpowered from all the blowby. Guns that use the VL system are still popping up at airgun shows, where they now command $150-225, depending on condition. The cased presentation models have always gone for more.

How to stop the detonatingApart from specific Webley and Weihrauch guns that have piston seals made of PTFE, stopping a spring gun from detonating is iffy. Some guns seem to detonate more than others. Cleaning the compression chamber and lubricating with a small amount of the correct lubricants is a surefire way, but it involves disassembly of the powerplant. You can sometimes solve the problem by putting a drop of high-flashpoint silicone oil into the chamber through the transfer port (or the oil hole in the case of a Mendoza). The high-flashpoint oil seems to dilute the other oils and greases to the point that they diesel but no longer detonate. This isn’t a positive solution, but I have seen it work.

Well, that turned out to be a longer answer than I thought it would be. But, now, when the subject of dieseling comes up, we have a place to turn to.

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37 thoughts on “What does dieseling mean? – Part 3”

BB,webley & weihrauch piston seals are not made of PTFE,THEY ARE MADE OF POLYPROPYLENE,and a good job to,i have an old HW80 witch i run with a t.r.robb piston seal made of PTFE, the problem with this is when it gets cold the washer shrinks, its good in a hot climate, you should only lubricate the washer with one drop of silicone oil, around the seals rim,and this would last for meney thousands of rounds,you cannot lube your spring or chamber in the normal way because the oil will get in front of the seal, with almost every shot your gun will be diesiling,you do get more power out of your gun with theas seals but ther are no were near consistant,as delring or polypropylene thats why they dont use them

Sorry to be so vague. Which would you recommend?. I understand for the money these are not top notch air rifles. I have a 800x and have been very happy for the most part. I know you have done an article on the Gamo 1000. I did’t know if you had shot any of the winchesters 1000x or 1000b. Supposedly the 1000b has some improvements over the 1000x.

BB,whats the gamo hunter extremes accuracy like,even at 1400 fps thats alote of power for a .177,i have seen the video with the pig being shot, but could ther be any real application in the wourld of hunting for this gun when i say about the accuracy i mean out to 50 yards what sort of groups would you exspect to get,could you get all of the pellets inside a 2 inch circle? or are we talking about pigs heads at 10 yards!

well, it seems like some ppl have luck with the extreme, when others don’t…on the cabelas website, they allow you to write reviews on products, and one person stands out in my mind saying that they got inch groupings with pba ammo in the extreme at 65 yrds…whether or not they are telling the truth, i know not, but there are other reports of people having a very accurate extreme. however, if a normal pellet does happen to go that much above the speed of sound, you can expect 3 inch groupings at 10 yards or worse!! i can tell you right now that bb doesnt like the pba ammo, and i feel the same way…completely false advertising, and you don’t get the penetration that is promised.

i have read a lot of reviews about the winchester 1000B, and a lot of people say they own a shadow and winchester, and the winchester has more power(and more sound)…i haven’t tested one, so i can’t tell you for sure…but i do have a ?…a lot of people say their stocks shattered after a few hundred shots, and i just wanted to know if that is a result of loosened screws or not, because i am looking into buying one, but i want to know everything about it first. thanks bb.

I think the Gamo Hunter Extreme is probably a pretty nice air rifle. The Hunter 1250 certainly was, and the Hunter Extreme is based on the 1250, I believe.

But it’s very difficult to shoot tight groups at 50 yards with a spring rifle. And a breakbarrel is the hardest of all. A BAM B40 would be a much easier rifle to shoot good groups at 50 yards and still have good hunting accuracy, and a TX200 would be best of all.

Hi BB,This doesnt have to do with dieseling, but I dont know where to ask a question in general when I have one. So I’m asking you here.

It is said that ANY gun cannot shoot any faster than the speed of sound in the propellent that the gun uses (under whatever conditions prevail). I can see that some airguns can indeed shoot 1400+ fps which is certainly faster than speed of sound in air (forget the accuracy right now).

Wanted to know your thoughts on this. Also, since I’m interested in internal ballistics, is there any written work on this aspect of airguns ? I am looking for a good physics description / analysis coz thats the only way I understand it well.

I don’t believe the report on the Cabelas site. I once knew a man who claimed to shoot a Crosman 760 at tin cans at a distance of a quarter-mile. Claimed he hit them all the time.

At 65 yards I believe any good shooter shooting a Hunter Extreme would be hard-pressed to keep a five-shot group under three inches. That’s with GOOD pellets. With PBAs I don’t think they could stay under 12 inches.

I read all the reviews and they do range from good to bad, though they all gave the rifle high marks for its appearance. One guy even thought that the Extreme is the most powerful airgun ever! Boy, is there a whole universe of more powerful airguns waiting for HIM!

Most reviewers thought the PBA was inaccurate, but a few said it was very accurate at long range.

The Gamo rifle are accurate, but not moreso than Weihrauchs or Air Arms.

The Daisy is a more powerful gun, it can easily shoot 50-100fps more than a Shadow. It tends to be quite accurate as well, in my hands it wasn’t much (if any) worse than my Shadow.

However, the gun is much, much less pleasant to shoot. It’s loud, it kicks, it is much harder to cock, and it has something of a reputation for mediocre durability. Shoot the Daisy for twenty minutes, and switching to the Gamo feels like a “vacation”.

The trigger and weight balance on the Gamo are superior, as is the overall workmanship. The Shadow had a lifetime warranty, the Daisy didn’t.

If you have to get internal parts for the Daisy (springs, seals) – forget it. Gamo does have some limited parts support, and there is some aftermarket support for it as well. Break the Daisy out of warranty, and you’re stuck with paying for factory service parts and labor.

i bought a hatsan mod. 60 .22 cal rifle for my son here in canada it is under the 500fps limit for non f.a.c. shooters but it hits very hard has very good accuracy and is very well built. i believe these winchesters are being made by them. in canada this rifle retails for $170-$200 which i think is preety good value for the money.

I often put an oil drop into pellet,especially when I want to surprise someone I’m using Gamo shadow 1000, with homemade gas ram powerplant. usually without diesel, it shoots 880fps.with diesel – 1130fps. Ok, I trust my gas ram strenght, seal replacement is not a problem at all, so what else can I break by shooting like this?Thank You.

You could also enlarge the compression cylinder, which is the frame of the gun. If that happens – no more airgun.

Finally, parts can fly off the airgun at speeds high enough to injure you or bystanders. In the 1960s I told a man that he should stop firing his damascus twist shotgun altogether. It was only proofed for black powder and after nearly a century, it probably had major internal rust – hidden from view. I didn’t make this up – it was a warning repeated in every gun magazine of the day.

But I was a teenager and he was an adult, so just to show me there was no danger, he put a high base shotgun shell in the gun and – blew it up in front of me. The parts flew like schrapnel from a hand grenade!

seems like i need to express the same sentiment here, that i used when answering a “double pellet loader”…..”just because you can do something, doesn’t mean you should do it”….and in the famous words of Blue Collar comedian Ron White, “LOOKS fade with time, but STUPID is forever”…

Also, I’m really curious about the Diana 460. Why does the Diana site claim several hundred fps less than everyone selling it (720 vs 1150)? So I’m really curious what it will really do. When you test one, would you please do the .22?

i think diana is one of a few companies that use higher weight pellets to test their guns. these figures on their web which i have also been on many times i believe reflect realistic velocities for most gun in this range.

i just finished reading all 3 parts to your review on the rws 54. when you get a chance to review the rws 460 magnum, please be as detailed as the rws 54. i will be trying to determine which of these two to plop my $500 down on once I have sufficient info. i am also hoping you will be testing this in .22 . thanks.

i find the velocities on diana’s website to be really confusing. in the pdf manual for the model 54 in .22 they have 230m/s = 900fps, and on the detail page its 760fps. for the 460 magnum its 235m/s = 780fps in the pdf manual, but 720fps on the detail page. confusing to say the least

last few questions have been about rws guns, which got me thinking. i’m trying to decide between the rws350 magnum, and the 52/54 models. i’ve read ur previous posts and comments, and the one thing i know is that “i don’t want to lose any fingers”. what do i mean? i noticed your reviews about the rws52, and if a person wasn’t careful loading the chamber, their fingers could be cut off. does someone have to do something completely idiotic for this to happen, or do the safety mechanisms in place make this idiot proof and an impossibility that could never happen. if it is a possibility, what do i want to make sure “i do not do”?. thanks in advance.

p.s.- does the recoiless feature of the 54 really work, and is it worth the extra money, meaning, would i enjoy the 52 just as well with proper technique and the money left in my pocket.

You can lose finger with the 350 Magnum just as fast as with the sidelevers. But the Diana sidelevers have the mmost positive safety system in all the airgun world. I think it’s even better than the TX200′s, which is also great.

With some pellets it seems best, but with others that are also smooth, the accuracy doesn’t seem to be there. I do think the powerplant is suited to certain pellets, but accuracy is a category of its own.

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